武夷山不同种植模式下茶园土壤理化性质和酶活性的季节变化特征

Seasonal Dynamic Characteristics of Soil Physical and Chemical Properties and Enzyme Activities of Different Planting Patterns in the Wuyishan

土壤酶活性是表征土壤肥力水平和养分转化的重要指标,揭示种植模式和季节变化对茶园土壤酶活性影响,阐明影响茶园土壤酶活性变化的主要环境因子,为合理评估有机茶种植的土壤生态效应提供理论依据。结合野外调查和室内分析方法,以武夷山茶区3种类型样地,即林地(FD)、常规茶园(CT)和有机茶园(OT)为研究对象,测定了参与土壤碳、氮和磷循环的6种酶活性,研究不同种植模式下土壤酶活性的季节变化规律及影响因子。结果显示,与林地土壤相比,常规种植模式茶园土壤铵态氮、全磷、有效磷和有效钾含量显著增加,土壤全钾和pH显著降低;相比常规茶园,有机茶园土壤有机质和全氮含量显著增加,土壤全磷、有效磷、全钾和速效钾含量显著降低,土壤pH有所增加,土壤养分比例更为协调。种植模式和季节及其交互作用对土壤脲酶和过氧化氢酶活性影响显著。与林地土壤相比,常规茶园土壤脲酶、多酚氧化酶、过氧化氢酶和酸性磷酸酶活性下降了12.05%~63.55%,有机茶园土壤脲酶显著提高了324.95%,种植模式并未改变土壤硝酸还原酶活性。总体而言,夏秋季节(5月和8月)土壤脲酶、多酚氧化酶、蔗糖酶和酸性磷酸酶活性明显高于冬春季节(11月和2月),土壤硝酸还原酶和过氧化氢酶活性在春季最高。置换多元方差分析结果显示,种植模式对土壤整体理化性质的影响远大于季节变化。冗余分析结果显示,土壤环境因子解释了土壤酶活性变异的77.03%,土壤有机质、全氮、铵态氮、全磷、有效磷、全钾、有效钾和pH对土壤酶活性有显著或极显著的影响。综上所述,林地转变为茶园对土壤理化性质和酶活性产生显著影响,常规种植导致茶园土壤速效磷钾积累,土壤酶活性降低,有机种植提高了土壤酶活性,增强了土壤碳氮养分供应能力,具有良好的生态环境效应。

Tea(Camellia sinensis L.)is one of the most important and traditional economic crops widely cultivated in the subtropical regions of China,which are usually developed from forestland.Soil enzyme activity is an important indicator of soil fertility and nutrient transformation.The purpose of this study is to investigate the seasonal dynamic characteristics of soil properties and enzyme activities of different planting patterns in Wuyishan city,and to provide theoretical basis for reasonable evaluation of soil ecological effects of organic tea cultivation.In this paper,three different planting patterns(forestland,conventional and organic tea gardens)were selected as the research objects.Soil samples were collected in May,August,November and February from 2021 to 2022.The soil properties and enzyme activities(urease,nitrate reductase,polyphenol oxidase,catalase,invertase and acid phosphatase)were determined in different seasons,and the dynamic changes with seasons were also investigated.The results show that:comparing with the forestland,the contents of soil ammonium nitrogen,total phosphorus,available phosphorus and available potassium increased significantly in the conventional tea garden,while the total potassium and pH decreased significantly.Compared with the conventional tea garden,the soil organic matter and total nitrogen contents increased significantly in the organic tea garden.The soil total phosphorus,available phosphorus,total potassium and available potassium contents decreased significantly.The soil pH also increased,and the proportion of soil nutrients was more coordinated.The effects of planting pattern and season and their interactions on urease and peroxidase activities were significant.Compared with the forestland,the soil urease,polyphenol oxidase,catalase and acid phosphatase activities decreased by 12.05%to 63.55%in the conventional tea garden,while urease activities significantly increased by 324.95%in the organic tea garden,and the soil nitrate reductase activities were not changed by planting mode.In general,the soil urease,polyphenol oxidase,invertase and acid phosphatase activities were significantly higher in summer and autumn(May and August)than those in winter and spring(November and February).The highest soil nitrate reductase and catalase activities were found in spring(February).The results of permutational multivariate analysis of variance show that the effect of planting pattern on the overall soil physical and chemical properties was much greater than that of seasonal changes.Redundancy analysis shows that soil environmental factors explained 77.03%of the variation in soil enzyme activity,and the soil organic matter,total nitrogen,ammonium nitrogen,total phosphorus,soil available phosphorus,total potassium,available potassium and pH were the main driving factors of soil enzymes.In summary,the conversion of forestland into tea gardens has a significant impact on soil properties and enzyme activities.Conventional planting leads to the accumulation of available phosphorus and potassium in tea garden soil and the decrease of soil enzyme activity,while organic planting improves soil enzyme activity and enhances soil carbon and nitrogen nutrient supply capacity,and thus is beneficial for maintaining a sustainable ecosystem in tea garden soil.